You got to remember though, Keenan has been doing Cosby for years. Ever since All That and if I remember correctly, on Keenan and Kel. So he is use to doing the character for years now.
God, I barely remember him doing Cosby.
... And I STILL want to see one of the old All That characters of his at least once. Pierre Escargot, Superdude, Randy of "Cooking with Randy and Mandy"... Hell, even Lester Oaks: Construction Worker.
God, All That rocked back in the day.